I have a well established stellar reputation and I tell them to read all of my reviews first. A lot of my regulars are Americans whom have business here in B.C. or Alberta.
So they see me here for an appointment or dinner and then electronically deposit the travel funds. I then either meet them at our destination or travel with them. Sometimes it is 50% now and 50% during to assuage any misgivings. I never accept cash in person though unless we are in Canada.
I would never advertise I was travelling to the states, then try and work there. I love hawaii and go often. its just not worth the risk never being able to go back, if I was busted down there.